1) What is the pH of 3M KCl?

Question

2) In general, is Ag2SO4 considered soluble in water?

Answer 1

1) Neglecting activity coefficients, the pH of KCl is 7.
2)Ag2SO4 is considered a sparingly soluble salt. Solubility is here.
http://en.wikipedia.org/wiki/Silver_sulfate